The site of a garbage mountain or landfill is not uncommon to find in Indian cities these days. In fact, every city in India now has a site dedicated/allocated as man-made ‘dump site’, where the solid waste of the city is dumped and disposed of. It is estimated that some 800 million tonnes has been ‘disposed of’ in the 3,159 dump sites across the country, according to data from the Central Pollution Control Board (CPCB).

In New Delhi itself, we have three landfills/dump sites (Ghazipur, Bhalswa and Okhla), which have been in commission since the late 1990s and are still used by the city corporations to discard the waste. Over 28 million tonnes of waste lay at these landfill sites. The Ghazipur dump, which is currently at the height of 65 metres of garbage, is already in the running to be taller in height than national monuments like Qutub Minar and Taj Mahal. Bhalswa and Okhla sites have already been declared exhausted but the untreated waste is still being dumped there with no other place to go in the city. In a recent study, it has been submitted that these landfills have cost more than ₹450 crores in environmental degradation to the national capital so far. The big question is what kind of waste is being dumped in these landfills and why are the landfills so dangerous to human health and the environment.

Solid waste can be separated into five major categories: (i) biodegradable waste or organic waste (food and kitchen waste, green waste vegetables, flower, leaves, fruits and paper, etc.), (ii) inert and non-biodegradable waste (construction and demolition waste, dirt, debris, etc.), (iii) recyclable waste (plastic, paper, bottles, glasses, etc.), (iv) domestic hazardous waste (including sanitary pads, diapers, etc), and (v) e-waste (including batteries etc).

Landfilling technology has been found to be one of the cheapest and easiest ways of disposing the waste both globally and in India. However, the landfills/dump grounds used currently are not sustainable, as they have no foundation, leachate management or treatment facilities or protection areas. The collected waste is just collectively dumped in these areas. In India, 80% of the collected waste or estimated 31 million tonnes of collected waste/annually is dumped at the landfill sites. Waste at the landfills have been known to be one of the major sources of anthropogenic greenhouse gas (GHG) emissions and a key contributor to global warming.

When the waste is buried in landfills a complex series of chemical and biological reactions is initiated, where the organic/biodegradable part of the waste is broken down by microorganisms releasing harmful gasses, including methane and carbon dioxide. The composition of the landfill gasses is roughly 60% methane, 40% carbon dioxide and a small amount of non-methane organic compounds. The municipal solid waste generated by households is considered the third largest anthropogenic source of methane (CH4) emissions, constituting 11% of all global CH4 emissions.

Methane is a potent greenhouse gas 28 to 36 times more effective than CO2 at trapping heat in the atmosphere over a 100-year period, and currently is the second largest contributor to global warming. India is considered as one of the top emitters of methane gas in the world with 409 million tonne CO2e generated in 2016, of which 14.46% was from the waste sector. The emission of GHGs from waste in India is also twice the global average.